Microstructures and Properties of High Performance Cast Irons Applied in Automobile Flywheels
Abstract
High performance cast iron (HPCI) with improved mechanical properties and balanced thermal conductivity is a strong candidate to replace ductile iron in the application of automobile flywheel. In this work, the relationship between microstructures and properties, including mechanical and thermal properties, of the grey cast iron were investigated by analysing some commercial flywheels. The results showed that the content of graphite was dependent on the content of carbon in the grey cast irons, and the simulation results indicated that most of carbon directly formed into graphite at room temperature (RT). High ultimate tensile strength (UTS) is caused by low area fraction and short length of the graphite. The thermal conductivity increased with increase of the area fraction of graphite. The short length of graphite would also contribute to thermal conductivity since a large number of the short graphite flakes formed under the circumstance of the similar area fraction of graphite. In order to get HPCI, the microstructures with a moderate area fraction and short length of graphite should be controlled.
Keywords
High performance cast iron (HPCI) Grey cast iron Microstructure Type A graphite Thermal conductivity Ultimate tensile strengthNotes
Acknowledgements
The authors would like to acknowledge W. Y. Yang and Y. R. Zheng for the assistance of useful discussions. The financial support provided by Ford Motor Company (University Research Program, 2014-5121R) is also acknowledged.
References
- 1.O. Oloyede, T.D. Bigg, R.F. Cochrane, A.M. Mullis, Microstructure evolution and mechanical properties of drop-tube processed, rapidly solidified grey cast iron. J. Mater. Sci. Eng. A 654, 143–150 (2016)CrossRefGoogle Scholar
- 2.R.J. Brown, Foseco Ferrous Foundryman’s Handbook, 11th edn. (Butterworth-Heinemann, 2000)Google Scholar
- 3.A. Velichko, A. Wiegmann, F. Mücklich, Structure and property studies on austempered and as-cast ausferritic gray cast irons. J. Acta Mater. 57, 5023–5035 (2009)CrossRefGoogle Scholar
- 4.P. Lan, J. Zhang, Strength, microstructure and chemistry of ingot mould grey iron after different cycles of low frequency high temperature loads. J. Mater. Des. 54, 112–120 (2014)CrossRefGoogle Scholar
- 5.M. Moonesana, A. Honarbakhsh Raoufa, F. Madahb, A. Habibollah Zadeh, Effect of alloying elements on thermal shock resistance of gray cast iron. J. Alloys Compd. 520, 226–231 (2012)CrossRefGoogle Scholar
- 6.M.C. Rukadikar, G. Reddy, Influence of chemical composition and microstructure on thermal conductivity of alloyed pearlitic flake graphite cast irons. J. Mater. Sci. 21, 4403–4410 (1986)CrossRefGoogle Scholar
- 7.EN ISO 945-1: 2008. Microstructure of cast irons–Part 1, 2010Google Scholar
- 8.D. Holmgren, R. Källbom, I.L. Svensson, Influences of the graphite growth direction on the thermal conductivity of cast iron. J. Metall. Mater. Trans. A 38, 268–275 (2007)CrossRefGoogle Scholar
- 9.D. Holmgren, I.L. Svensson, Thermal conductivity–structure relationships in grey cast iron. Int. J. Cast Metals Res. 18, 321–330 (2005)CrossRefGoogle Scholar
- 10.J. Leitner, P. Chuchvalec, D. Sedmidubský, A. Strejc, P. Abrman, Application of Neumann-Kopp rule for the estimation of heat capacity of mixed oxides. J. Thermochim. Acta 395, 27–46 (2002)CrossRefGoogle Scholar
- 11.C.L. Zhang, Y.L. Pei, L.D. Zhao, D. Berardan, N. Dragoe, S.K. Gong, H.B. Guo, The phase stability and thermophysical properties of InFeO3(ZnO)m (m = 2, 3, 4, 5). J. Eur. Ceram. Soc. 34, 63–68 (2014)CrossRefGoogle Scholar
- 12.L. Collini, G. Nicoletto, R. Konečná, Microstructure and mechanical properties of pearlitic gray cast iron. J. Mater. Sci. Eng. A 488, 529–539 (2008)CrossRefGoogle Scholar
- 13.A. Vadiraj, G. Balachandran, M. Kamaraj, Structure–property correlation in austempered alloyed hypereutectic gray cast irons. J. Mater. Design 30, 4488–4492 (2009)CrossRefGoogle Scholar